1. Field of the Invention
Exemplary embodiments of the present invention relate to a photoalignment material and a method of manufacturing a display substrate using the photoalignment material.
2. Description of the Background
Generally, liquid crystal display (LCD) devices have been in great demand as the display industry has grown. Advances in LCD devices include low driving voltages, high resolutions, slim sizes, and flat screens. One of the core manufacturing techniques of LCD devices is a photoalignment technique to align liquid crystals in a desired direction by using ultraviolet (UV) light.
To form an alignment layer, static electricity may be generated using a rubbing cloth during a rubbing process; however, a display substrate of the LCD may be damaged by the static electricity. Moreover, the display substrate may easily be polluted and stained in the rubbing process, so that a display quality of the LCD may decrease. In order to prevent damage from static electricity and to improve the display quality, a photoalignment process is needed, wherein the process may include spreading a photoalignment material on the base substrate and photolyzing, photoisomerizing, or photopolymerizing the photoalignment material using light.
Generally, in a photoalignment layer, a photoreactive group coupled to a side chain of a polyimide may be irradiated with UV light to align liquid crystals in an irradiation direction. Active research has been conducted on the photoalignment process to simplify the process and make the process more convenient in comparison to the rubbing process. However, physical, chemical, electrical and electronic characteristics of the aligned liquid crystal layer are still weak, and thus mass production may still be difficult.
In addition, in a photoalignment process, a liquid crystal alignment may be induced by a light reaction. However, a voltage holding ratio (VHR) may be reduced, and afterimages may become worse due to a side reaction caused by polarized and non-polarized UV irradiation of the photoreactive polymer. The display quality of the LCD panel may thus deteriorate.